Mental states (belief, desire etc. ) consciousness (feelings, sensations etc. What is described by physics physical states (mass, shape, electric charge etc. ) The mind-body problem = explaining the relationship between the mental and the physical. The source of the modern mind-body problem is descartes. Dualism versus materialism dualism = the view that mind and matter are different things. Materialism = the view that mind is a part of the material world which is all there is. Mind is a separate entity: mind is non-spatial (has no size, no location) Mind is in causal interaction with matter: eg. injury to body causes painful feeling in mind, eg. mental decision to raise arm causes arm to rise. One form of materialism is the mind-brain identity theory. Mind is identical to brain analogy with the discovery that water h20: neuroscience will discover that mind = brain.